Q & A: Keeping Corn Plus in the Sweet Spot
Calculating the current ethanol yield at Corn Plus LLLP is Courtney Trask’s first duty when she reports to work at the 49 MMgy facility in Winnebago, Minn., each morning. As lab manager, Trask monitors pH and glucose levels, temperature and yeast health plantwide, all with an eye toward achieving maximum ethanol production. In her perpetual quest to optimize Corn Plus for ethanol, DDGS and corn-oil production while keeping bacterial infection at bay, the South Dakota State University graduate enlists the help of vendors, co-workers and peers she has met at industry events.
When and where did your interest in science begin?
Growing up on a cattle ranch in Western South Dakota gave me exposure to science at a young age. When we would treat our cattle or calves I was always a little curious about how the treatment actually worked. I knew as soon as I entered high school that I wanted to attend college to earn my doctorate degree in pharmacy. As my college career began, my plans didn’t quite work out so I decided to go with the next science-based degree that I had a strong interest in, which led me to receive my (bachelor of science) in microbiology. I had no idea that my interest in microbiology would lead me to the places that it has in my career.
What were your first days as a lab manager like?
The learning curve was definitely steep. There is a lot to learn, and it can sometimes be overwhelming. I relied—and still do—heavily on my fellow employees, as well as vendors, to help decrease that overwhelming feeling. I attended several industry events right away and had the opportunity to create relationships with other lab managers in the industry. These relationships have also helped me become more familiar with the field and have allowed me to make more informed decisions.
Talk a little about the counsel your vendors provide and how you utilize it as you go about your day.
The ethanol process is monitored using a combination of high performance liquid chromatography (HPLC), pH, Brix, temperature, and yeast counts. Our fermentation process is also monitored every six hours, which means that each of the variables is different for each time during fermentation. Our vendors have been extremely helpful in sorting out which information is the most important to keep an eye on as well as what the numbers should look like at each hour. They have also been able to quickly analyze our data when our plant is struggling. Our HPLC rep has also been a huge help with assisting me in understanding our HPLC software to ensure we are getting accurate numbers. I also use my vendors when our plant is experiencing something that I haven’t seen before; their knowledge is vast because they work with so many plants.
In the sea of numbers you are constantly measuring and analyzing, what is the one number you look at first each morning?
Ethanol is what we were built to do, so that is definitely the number that I look at first. If these numbers are lower than I like to see, I begin looking at the multiple variables that can cause a fermenter to not finish with the desired amount of ethanol. The first variable that I turn to is glucose. This number is important in judging how well the fermenter performed because yeast utilizes the glucose to produce ethanol. This means that if the glucose number is high, the yeast could have utilized more of the glucose to produce more ethanol. When this is the case, then I start looking into the multiple factors that could cause yeast stress. It is indeed a very data-driven process, and it’s an important part of my job to use the available data to make decisions about the performance of the plant.
How much variance do you experience in the data you measure each day? Do your yields fluctuate quite a bit?
Our yield does fluctuate more than I would like to see. There are just so many variables that are involved, that it can sometimes be difficult to determine where the problem may be coming from. It isn’t uncommon to make several changes before you find the root cause of the problem. I do believe that as the plant becomes even more data-driven and as I become more comfortable with analyzing the data that the plant will begin to run more smoothly, and it will be easier to narrow down the source of the problem.
Do you see patterns emerging in the variations you see in the lab? Are there certain points in the process that end up on a short list of usual suspects?
Patterns do tend to show up in the lab data. We like to say in this industry that “trends are your friends.” They often help to determine the source of the problem. There are definitely things that end up on a short list of usual suspects. These things are often verified by the trends that we see in the data.
What can you tell me about the samples pulled from the plant each day?
We have nine fermenters here at Corn Plus. Currently seven of those fermenters are online, and being tested every six hours. This means there are roughly 15 to 20 fermentation samples per shift, which means there can be close to 40 fermentation samples every 24 hours. This is only our fermentation samples. There are also multiple samples that the lab as well as the operators take every few hours or at least once daily to ensure that the plant is running smoothly.
Can you explain what happens in a bacterial infection at an ethanol plant?
Bacterial infections are most often caused by some type of dead leg in the process which is an area that cannot be properly cleaned. The corn mash can sit in this area, which just so happens to be the perfect pH, temp, and food source for bacteria growth to flourish. This can also be caused by improper cleaning, weak cleaning solution, or a multitude of other variables. From a microbiologist standpoint, I learned this piece of advice from a vendor just recently. If you have a pocket or dead leg of bacteria with a total cell count of 108, it only takes 1 gallon of that high bacterial contaminated mash into 1,000 gallons of clean mash to turn the clean mash into a 105 environment. In this industry, anything 105 or higher is considered an infection, so 1 gallon of infected mash can create a high risk environment early in fermentation.
It seems there is a sweet spot you are working to achieve and maintain from a production standpoint. Is this difficult to hold, or are you simply making minor adjustments to hold that position once it’s established?
There is definitely a sweet spot that we would like to run and I feel that we will get to a point where we can make only minor adjustments to keep within the sweet spot parameters. Our situation is difficult right now because we have implemented so many new things at the plant in the past few months. I strongly believe that the more and more comfortable we get with the new equipment the easier it will be to maintain the sweet spot for good production. I also understand that stuff happens and there will more than likely always be a threat for a situation to occur. The best we can do is become knowledgeable about the decisions that we make, and above all make decisions based on data.